1. Field of the Invention
The present invention relates generally to mobile communication systems, and more specifically to a mobile communication system wherein mobile stations have outdoor and indoor modes of operation.
2. Description of the Related Art
A prior art technique as typically disclosed in Japanese Laid-Open Patent Specification Hei-4-23340 involves the use of radio communication for outdoor use and optical communication for indoor use. The use of optical communication medium for indoor use is to avoid interference with other mobile stations. However, if a mobile station is entering a building from the outside while communicating with a base station, the ongoing call must be interrupted to switch over to the optical communication mode if the user still desires to continue the communication.
Therefore, a need for uniterrupted communication exists for mobile stations when they change modes between outdoor communication and indoor communication.